Electroacupuncture preconditioning attenuates ischemic brain injury by activation of the adenosine monophosphate-activated protein kinase signaling pathway

Electroacupuncture has therapeutic effects on ischemic brain injury, but its mechanism is still poorly understood. In this study, mice were stimulated by electroacupuncture at the Baihui（GV20） acupoint for 30 minutes at 1 m A and 2/15 Hz for 5 consecutive days. A cerebral ischemia model was established by ligating the bilateral common carotid artery for 15 minutes. At 72 hours after injury, neuronal injury in the mouse hippocampus had lessened, and the number of terminal deoxynucleotide transferase-mediated d UTP nick-end labeling-positive cells reduced after electroacupuncture treatment. Moreover, expression of adenosine monophosphate-activated protein kinase α（AMPKα） and phosphorylated AMPKα was up-regulated. Intraperitoneal injection of the AMPK antagonist, compound C, suppressed this phenomenon. Our findings suggest that electroacupuncture preconditioning alleviates ischemic brain injury via AMPK activation.

Metformin attenuates motility,contraction,and fibrogenic response of hepatic stellate cells in vivo and in vitro by activating AMP-activated protein kinase

AIM To investigate the effect of metformin on activated hepatic stellate cells(HSCs) and the possible signaling pathways involved. METHODS A fibrotic mouse model was generated by intraperitoneal injection of carbon tetrachloride(CCl_4) and subsequent treatment with or without metformin. The level of fibrosis was detected by hematoxylin-eosin staining, Sirius Red staining, and immunohistochemistry. The HSC cell line LX-2 was used for in vitro studies. The effect of metformin on cell proliferation(CCK8 assay),motility(scratch test and Transwell assay), contraction(collagen gel contraction assay), extracellular matrix(ECM) secretion(Western blot), and angiogenesis(ELISA and tube formation assay) was investigated. We also analyzed the possible signaling pathways involved by Western blot analysis.RESULTS Mice developed marked liver fibrosis after intraperitoneal injection with CCl_4 for 6 wk. Metformin decreased the activation of HSCs, reduced the deposition of ECM, and inhibited angiogenesis in CCl_4-treated mice. Platelet-derived growth factor(PDGF) promoted the fibrogenic response of HSCs in vitro, while metformin inhibited the activation, proliferation, migration, and contraction of HSCs, and reduced the secretion of ECM. Metformin decreased the expression of vascular endothelial growth factor(VEGF) in HSCs through inhibition of hypoxia inducible factor(HIF)-1α in both PDGF-BB treatment and hypoxic conditions, and it down-regulated VEGF secretion by HSCs and inhibited HSC-based angiogenesis in hypoxic conditions in vitro. The inhibitory effects of metformin on activated HSCs were mediated by inhibiting the Akt/mammalian target of rapamycin(m TOR) and extracellular signal-regulated kinase(ERK) pathways via the activation of adenosine monophosphate-activated protein kinase(AMPK).CONCLUSION Metformin attenuates the fibrogenic response of HSCs in vivo and in vitro, and may therefore be useful for the treatment of chronic liver diseases.

Role of Activator Protein-1 in the Transcription of Interleukin-5 Gene Regulated by Protein Kinase C Signal in Asthmatic Human TLymphocytes

Summary: In order to explore the role of activator protein-1 (AP-1) in the transcription of interleukin-5 (IL-5) gene regulated by protein kinase C (PKC) signal in peripheral blood T lymphocytes from asthmatic patient, T lymphocytes were isolated and purified from peripheral blood of each asthmatic patient. The T lymphocytes were randomly divided into 4 groups: group A (blank control), group B (treated with PKC agonist phorbol 12-myristate 13-acetate (PMA)), Group C (treated with PMA and AP-1 cis-element decoy oligodeoxynucleotides (decoy ODNs)), and group D (treated with PMA and AP-1 mutant decoy ODNs). The ODNs were transfected into the T cells of group C and D by cation liposome respectively. Reverse transcription-polymerase chain reaction (RT-PCR) was employed to assess IL-5 mRNA expression, and electrophoretic mobility shift assays (EMSA) for the activation of AP-1. The results showed that the activation of AP-1 (88 003.58±1 626.57) and the expression of IL-5 mRNA (0.8300±0.0294) in T lymphocytes stimulated with PMA were significantly higher than these in blank control (20 888.47±1103.56 and 0.3050±0.0208, respectively, P< 0.01), while the indexes (23 219.83±1 024.86 and 0.3425±0.0171 respectively) of T lymphocytes stimulated with PMA and AP-1 decoy ODNs were significantly inhibited, as compared with group B (P< 0.01). The indexes (87 107.41±1 342.92 and 0.8225±0.0222, respectively) in T lymphocytes stimulated with PMA and AP-1 mutant decoy ODNs did not exhibit significant changes, as compared with group B (P>0.05). The significant positive correlation was found between the activation of AP-1 and the expression of IL-5 mRNA (P< 0.01). It was concluded that AP-1 might participate in the signal transduction of PKC-triggered transcription of IL-5 gene in asthmatic T lymphocytes. This suggests the activation of PKC/AP-1 signal transduction cascade of T lymphocytes may play an important role in the pathogenesis of asthma.

Dan-gua Fang (丹瓜方) Improves Glycolipid Metabolic Disorders by Promoting Hepatic Adenosine 5'-monophosphate Activated Protein Kinase Expression in Diabetic Goto-kakizaki Rats

Objective：To investigate the effect of Dan-gua Fang（丹瓜方） on adenosine 5’-monophosphate（AMP） activated protein kinase（AMPK） α expression in liver and subsequent improvement of glucose and lipid metabolism.Methods：Forty 13-week-old diabetic Goto-Kakizaki（GK） rats were randomly divided into model,Dan-gua Fang,metformin and simvastatin groups（n=10 for each）,and fed high-fat diet ad libitum.Ten Wistar rats were used as normal group and fed normal diet.After 24 weeks,liver expression of AMPK α mRNA was assessed by real-time PCR.AMPK α and phospho-AMPK α protein expression in liver was evaluated by Western blot.Liver histomorphology was carried out after hematoxylin-eosin staining,and blood glucose（BG）,glycosylated hemoglobin A1c（HbA1c）,food intake and body weight recorded.Results：Similar AMPK α mRNA levels were found in the Dan-gua Fang group and normal group,slightly higher than the values obtained for the remaining groups（P〈0.05）.AMPK α protein expression in the Dan-gua Fang group animals was similar to other diabetic rats,whereas phospho-AMPK α（Thr-172） protein levels were markedly higher than in the metformin group and simvastatin group（P〈0.05）,respectively.However,phosphor-AMPKa/AMPK α ratios were similar in all groups.Dan-gua Fang reduced fasting blood glucose with similar strength to metformin,and was superior in reducing cholesterol,triglycerides,high-density lipoprotein cholesterol as well as improving low-density lipoprotein cholesterol in comparison with simvastatin and metformin.Dan-gua Fang decreases plasma alanine aminotransferase（ALT） significantly.Conclusion：Dan-gua Fang,while treating phlegm-stasis,could decrease BG and lipid in type 2 diabetic GK rats fed with high-fat diet,and effectively protect liver histomorphology and function.This may be partly explained by increased AMPK expression in liver.Therefore,Dan-gua Fang might be an ideal drug for comprehensive Intervention for glucose and lipid metabolism disorders in type 2 diabetes mellitus.

白花蛇舌草提取物通过AMPK/ATG5信号通路对急性胰腺炎大鼠肺损伤的保护作用机制研究

目的:通过5’-单磷酸腺苷活化蛋白激酶(AMPK)/自噬相关蛋白5(ATG5)信号通路,探讨白花蛇舌草提取物减轻急性胰腺炎(AP)大鼠肺损伤的机制。方法:建立AP肺损伤大鼠模型,随机分为模型组、提取物(白花蛇舌草提取物)组、3-MA(自噬抑制剂3-甲基腺嘌呤)组、AICAR(AMPK激活剂)组、提取物+AICAR组,每组15只,另取15只大鼠作为假手术组;ELISA检测血清淀粉酶(AMY)、IL-1β、IL-6、IL-18水平;检测大鼠腹水量及肺湿/干重比(W/D);HE观察胰腺及肺组织病理损伤;Western blot检测溶酶体相关膜蛋白2(LAMP2)、自噬底物p62、IL-1β前体蛋白(pro-IL-1β)、胰蛋白酶原活化肽(TAP)、AMPK、p-AMPK、ATG5、自噬标志物LC3-Ⅱ/Ⅰ、泛素特异性蛋白酶10(UPS10)表达。结果:与假手术组相比,模型组大鼠腹水量、肺W/D、胰腺和肺组织病理损伤评分、血清AMY、IL-1β、IL-6、IL-18水平、胰腺组织p62、TAP、pro-IL-1β表达、肺组织pAMPK/AMPK、ATG5、LC3-Ⅱ/Ⅰ、UPS10、pro-IL-1β表达均升高(P<0.05),胰腺和肺组织LAMP2蛋白表达降低(P<0.05);模型大鼠经白花蛇舌草提取物或自噬抑制剂3-MA干预后,上述指标均得到显著改善(P<0.05),且白花蛇舌草提取物的改善效果优于3-MA(P<0.05);而AMPK激活剂AICAR可削弱白花蛇舌草提取物对AP大鼠肺损伤的改善作用(P<0.05)。结论:白花蛇舌草提取物可通过抑制AMPK/ATG5信号通路减轻炎症反应、降低自噬水平改善AP大鼠肺损伤。

Mechanisms of extracellular signal-regulated kinase/cAMP response element-binding protein/brain-derived neurotrophic factor signal transduction pathway in depressive disorder

The extracellular signal-regulated kinase/cAMP response element-binding protein/brain-derived neurotrophic factor signal transduction pathway plays an important role in the mechanism of action of antidepressant drugs and has dominated recent studies on the pathogenesis of depression. In the present review we summarize the known roles of extracellular signal-regulated kinase, cAMP response element-binding protein and brain-derived neurotrophic factor in the pathogenesis of depression and in the mechanism of action of antidepressant medicines. The extracellular signal-regulated kinase/cAMP response element-binding protein/brain-derived neurotrophic factor pathway has potential to be used as a biological index to help diagnose depression, and as such it is considered as an important new target in the treatment of depression.

微RNA-375-5p对心力衰竭大鼠的保护作用及机制

目的探讨微RNA(miR)-375-5p对心力衰竭(HF)大鼠的保护作用及相关机制。方法将50只雄性Sprague Dawley大鼠随机分为假手术组、HF组、miR-NC组、miR-375-5p组、miR-375-5p+Compound C(CC)组,每组10只。HF组、miR-NC组、miR-375-5p组、miR-375-5p+CC组大鼠腹腔注射阿霉素溶液制备HF模型,假手术组大鼠腹腔注射等量的NaCl溶液。造模结束后次日,miR-375-5p组大鼠经尾静脉注射miR-375-5p mimics 100μL,miR-NC组大鼠经尾静脉注射miR-NC mimics 100μL,假手术组和HF组大鼠经尾静脉注射等量生理盐水,miR-375-5p+CC组大鼠经尾静脉注射miR-375-5p mimics 100μL和腺苷酸活化蛋白激酶(AMPK)抑制剂CC(0.2 mg·kg^(-1));各组大鼠均每日给药1次,连续给药4周。使用彩色多普勒超声仪检测各组大鼠心功能指标,反转录聚合酶链反应检测各组大鼠心肌组织中miR-375-5p表达,酶联免疫吸附试验检测各组大鼠血清中肿瘤坏死因子-α(TNF-α)、白细胞介素(IL)-6、IL-1β、丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽(GSH)水平,苏木精-伊红染色观察各组大鼠心肌组织病理学变化,末端脱氧核苷酸转移酶介导的末端标记法检测各组大鼠心肌细胞凋亡情况,蛋白质印迹检测各组大鼠心肌组织中磷酸化腺苷酸活化蛋白激酶(p-AMPK)、AMPK、沉默信息调节因子3(SIRT3)蛋白的相对表达量。结果与假手术组比较,HF组、miR-NC组和miR-375-5p组大鼠的左心室射血分数(LVEF)、左心室短轴缩短率(LVFS)、血清中SOD活性、GSH水平及心肌组织中p-AMPK/AMPK、miR-375-5p表达量和SIRT3蛋白相对表达量显著降低,左心室舒张末期内径(LVEDD)、左心室收缩末期内径(LVESD)、心肌细胞凋亡率及血清中TNF-α、IL-6、IL-1β、MDA水平显著升高(P<0.05)。miR-NC组与HF组大鼠LVEF、LVFS、LVEDD、LVESD、心肌细胞凋亡率、血清中TNF-α、IL-6、IL-1β、MDA、GSH水平、SOD活性、心肌组织中p-AMPK/AMPK、miR-375-5p表达量及SIRT3蛋白相对表达量比较差异无统计学意义(P>0.05)。与HF组相比,miR-375-5p组大鼠LVEF、LVFS、血清中SOD活性、GSH水平、心肌组织中p-AMPK/AMPK及miR-375-5p表达量和SIRT3蛋白相对表达量显著升高,LVEDD、LVESD、心肌细胞凋亡率及血清中TNF-α、IL-6、IL-1β、MDA水平显著降低(P<0.05)。与miR-375-5p组相比,miR-375-5p+CC组大鼠LVEF、LVFS、血清中SOD活性、GSH水平及心肌组织中p-AMPK/AMPK、miR-375-5p表达量和SIRT3蛋白相对表达量显著降低,LVEDD、LVESD、心肌细胞凋亡率及血清中TNF-α、IL-6、IL-1β、MDA水平显著升高(P<0.05)。假手术组大鼠心肌细胞规律排列,细胞核明显且无炎症细胞浸润;HF组大鼠心肌细胞形态发生明显改变,排列紊乱,细胞间隙变大,染色变浅,且出现心肌纤维化,有大量的炎症细胞浸润,HF组和miR-NC组大鼠心肌组织病理学变化无明显差异;与HF组相比,miR-375-5p组大鼠心肌细胞排列明显有序,细胞坏死程度和范围明显减少;miR-375-5p+CC组与HF组大鼠心肌组织病理学变化相似。结论miR-375-5p能抑制HF大鼠心肌细胞凋亡,进而对HF大鼠发挥保护作用,其机制可能与激活AMPK/SIRT3信号通路有关。

Amino acids regulate energy utilization through mammalian target of rapamycin complex 1 and adenosine monophosphate activated protein kinase pathway in porcine enterocytes

As major fuels for the small intestinal mucosa,dietary amino acids(AA)are catabolized in the mitochondria and serve as sources of energy production.The present study was conducted to investigate AA metabolism that supply cell energy and the underlying signaling pathways in porcine enterocytes.Intestinal porcine epithelial cells(IPEC-J2)were treated with different concentrations of AA,inhibitor,or agonist of mammalian target of rapamycin complex 1(mTORCl)and adenosine monophosphate activated protein kinase(AMPK),and mitochondrial respiration was monitored.The results showed that AA treatments resulted in enhanced mitochondrial respiration,increased intracellular content of pyruvic acid and lactic acid,and increased hormone-sensitive lipase mRNA expression.Meanwhile,decreased citrate synthase,isocitrate dehydrogenase alpha,and carnitine palmitoyltransferase 1 mRNA expression were also observed.We found that AA treatments increased the protein levels of phosphorylated mammalian target of rapamycin(p-mTOR),phosphorylated-p70 ribosomal protein S6 kinase,and phosphorylated-4 E-binding protein 1.What is more,the protein levels of phosphorylated AMPKα(pAMPKa)and nicotinamide adenine dinucleotide(NAD)-dependent protein deacetylase sirtuin-1(SIRT1)were decreased by AA treatments in a time depending manner.Mitochondrial bioenergetics and the production of tricarboxylic acid cycle intermediates were decreased upon inhibition of mTORCl or AMPK.Moreover,AMPK activation could up-regulate the mRNA expressions of inhibitor of nuclear factor kappa-B kinase subunit beta(Ikbk(3),integrin-linked protein kinase(ILK),unconventional myosin-Ic(Myolc),ribosomal protein S6 kinase beta-2(RPS6 Kβ2),and vascular endothelial growth factor(VEGF)-β,which are downstream effectors of mammalian target of rapamycin(mTOR).The mRNA expressions of phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit delta isoform(PIK3 CD)and5’-AMP-activated protein kinase subunit gamma-1(PRKAG1),which are upstream regulators of mTOR,were also up-regulated by AMPK activation.On the other hand,AMPK activation also down-regulated FK506-binding protein 1 A(FKBP1 A),serine/threonine-protein phosphatase 2 A 55 kDa regulatory subunit B beta isoform,phosphatase and tensin homolog(PTEN),and unc-51 like autophagy activating kinase 1(Ulkl),which are up-stream regulators of mTORCl.Taken together,these data indicated that AA regulated cellular energy metabolism through mTOR and AMPK pathway in porcine enterocytes.These results demonstrated interactions of AMPK and mTORCl pathways in AA catabolism and energy metabolism in intestinal mucosa cells of piglets,and also provided reference for using AA to remedy human intestinal diseases.

Beneficial effects of metformin on primary cardiomyocytes via activation of adenosine monophosphate-activated protein kinase

Background Metformin has become a cornerstone in the treatment of patients with type-2 diabetes. Accumulated evidence suggests that metformin supports direct cardiovascular effects. The present study aimed to investigate if metformin has beneficial effects on primary cardiomyocytes damaged by H2O2, and reveal the potential mechanism of action of metformin. Methods Cardiomyocytes were incubated in the presence of 100μmol/L H2O2 for 12 hours. Cardiomyocytes were pretreated with metformin at different concentrations and time and with aminoimidazole carboxamide ribonucleotide （AICAR） （500μmol/L）, an adenosine monophophate （AMP）-activated protein kinase （AMPK） agonist for 60 minutes before the addition of H2O2. Other cells were preincubated with compound C （an AMPK antagonist, 20μmol/L） for 4 hours. The viability and apoptosis of cells were analyzed. AMPK, endothelial nitric oxide synthase （eNOS）, and transforming growth factor （TGF）-β1 were analyzed using immunblotting. Results Metformin had antagonistic effects on the influences of H2O2 on cell viability and attenuated oxidative stress-induced apoptosis. Metformin also increased phosphorylation of AMPK and eNOS, and reduced the expression of TGF-β1, basic fibroblast growth factor （bFGF）, and tumor necrosis factor （TNF）-α. Conclusions Metformin has beneficial effects on cardiomyocytes, and this effect involves activation of the AMPK-eNOS pathway. Metformin may be potentially beneficial for the treatment of heart disease.

Metformin inhibits nuclear factor-κB activation and inflammatory cytokines expression induced by high glucose via adenosine monophosphate-activated protein kinase activation in rat glomerular mesangial cells in vitro

Background The renoprotective mechanisms of adenosine monophosphate （AMP）-activated protein kinase （AMPK） agonist-metformin have not been stated clearly.We hypothesized that metformin may ameliorate inflammation via AMPK interaction with critical inflammatory cytokines The aim of this study was to observe the effects of metformin on expression of nuclear factor-κB （NF-κB）,monocyte chemoattractant protein-1 （MCP-1）,intercellular adhesion molecule-1 （ICAM-1） and transforming growth factor-beta 1 （TGF-β1） induced by high glucose （HG） in cultured rat glomerular mesangial cells （MCs）.Methods MCs were cultured in the medium with normal concentration glucose （group NG,5.6 mmol/L）,high concentration glucose （group HG,25 mmol/L） and different concentrations of metformin （group M1,M2,M3）.After 48-hour exposure,the supernatants and MCs were collected.The expression of NF-κB,MCP-1,ICAM-1,and TGF-β1 mRNA was analyzed by real time polymerase chain reaction.Westem blotting was used to detect the expression of AMPK,phospho-Thr-172 AMPK （p-AMPK）,NF-κB p65,MCP-1,ICAM-1,and TGF-β1 protein.Results After stimulated by HG,the expression of NF-κB,MCP-1,ICAM-1,TGF-β1 mRNA and protein of MCs in group HG increased significantly compared with group NG （P ＜0.05）.Both genes and protein expression of NF-κB,MCP-1,ICAM-1,TGF-β1 of MCs induced by high glucose were markedly reduced after metformin treatment in a dose-dependent manner （P ＜0.05）.The expression of p-AMPK increased with the rising of metformin concentration,presenting the opposite trend,while the level of total-AMPK protein was unchanged with exposure to HG or metformin.Conlusion Metformin can suppress the expression of NF-κB,MCP-1,ICAM-1 and TGF-β1 of glomerular MCs induced by high glucose via AMPK activation,which may partlv contribute to its reno-protection.

Effects of Ginsenoside Rb1 on Skeletal Muscle Insulin Resistance and Adenosine Monophosphate?activated Protein Kinase Signaling Pathway in Obese Mice

Objectives: The objective of the study is to observe the effects of ginsenoside Rb1 on indexes of body weight, body composition, blood lipid, skeletal muscle endurance, and insulin sensitivity in obese mice, probe into its pharmacological action, and further explore its effects on adenosine monophosphate-activated protein kinase(AMPK) signaling pathway in skeletal muscle. Materials and Methods: Eight-week-old C57 BL/6 J mice were fed with high-fat diet for 12 weeks to establish obese mouse model. The model-establishment obese mice were randomly divided into three groups including model control group, metformin group, and ginsenoside Rb1 group. In the normal control group, normal diet was administered. The intervention period was 8 weeks. Body weight and food intake of the mice were measured regularly every week. The treadmill test was performed at weeks 3 and 7, and the oral glucose tolerance test was carried out at weeks 4 and 8. Body composition of the mice was detected by applying NMR Animal Body Composition Analyzer at week 8. Four parameters of blood lipids and free fatty acid(FFA)levels were detected. The m RNA expression of AMPKα and proliferator-activated receptor gamma coactivator-1α(PGC-1α) in skeletal muscle was examined by real-time fluorescence quantitative polymerase chain reaction, and the influence of ginsenoside Rb1 on protein expression of AMPKα, p-AMPKα, and PGC-1α was observed by western blotting. Results: The body weight(since the 5 th week of drug administration)and food intake of the mice in the ginsenoside Rb1 group were significantly lower than those in the model control group(P < 0.05) in a time-dependent manner. Ginsenoside Rb1 could significantly reduce the levels of triglyceride and low-density lipoprotein cholesterol, while increase the high-density lipoprotein cholesterol level(P < 0.05). In addition, ginsenoside Rb1 could reduce the serum FFA level(P < 0.05).After the administration of ginsenoside Rb1 for 8 weeks, the body fat mass of obese mice decreased and the lean mass increased(P < 0.05).The skeletal muscle endurance and the oral glucose tolerance of the obese mice improved using ginsenoside Rb1. At the molecular level,ginsenoside Rb1 could up-regulate the mRNA and protein expression of AMPKα in skeletal muscle, and increase the content of p-AMPK protein significantly(P < 0.01). At the same time, the mRNA and protein level of PGC-1α was also un-regulated, correspondingly(P < 0.01).Conclusion: Ginsenoside Rb1 exerts effects on reducing body weight, decreasing blood lipid levels, enhancing the skeletal muscle endurance,and increasing the insulin sensitivity in obese mice by activating the related proteins in AMPK signaling pathway in skeletal muscle.

Insulin-like growth factor binding protein-5 influences pancreatic cancer cell growth

AIM: To investigate the functional significance of insulin-like growth factor binding protein-5 (IGFBP-5) overexpression in pancreatic cancer (PaC).METHODS: The effects of IGFBP-5 on cell growth were assessed by stable transfection of BxPC-3 and PANC-1 cell lines and measuring cell number and DNA synthesis. Alterations in the cell cycle were assessed by flow cytometry and immunoblot analyses. Changes in cell survival and signal transduction were evaluated after mitogen activated protein kinase and phosphatidylinositol 3-kinase (PI3K) inhibitor treatment.RESULTS: After serum deprivation, IGFBP-5 expression increased both cell number and DNA synthesis in BxPC-3 cells, but reduced cell number in PANC-1 cells. Consistent with this observation, cell cycle analysis of IGFBP-5-expressing cells revealed accelerated cell cycle progression in BxPC-3 and G2/M arrest of PANC-1 cells. Signal transduction analysis revealed that Akt activation was increased in BxPC-3, but reduced in PANC-1 cells that express IGFBP-5. Inhibition of PI3K with LY294002 suppressed extracellular signal-regulated kinase-1 and -2 (ERK1/2) activation in BxPC-3, but enhanced ERK1/2 activation in PANC-1 cells that express IGFBP-5. When MEK1/2 was blocked, Akt activation remained elevated in IGFBP-5 expressing PaC cells; however, inhibition of PI3K or MEK1/2 abrogated IGFBP-5-mediated cell survival.CONCLUSION: These results indicate that IGFBP-5 expression affects the cell cycle and survival signal pathways and thus it may be an important mediator of PaC cell growth.

Coptidis Rhizoma Water Extract Stimulates 5'-AMP-Activated Protein Kinase in Rat Skeletal Muscle

AIM:Coptidis Rhizoma(CR),the dried rhizomes of Asian herbs(including Coptis chinensis Franch),has been used to treat diabetes mellitus for thousands of years.We explored the possibility that CR acts directly on skeletal muscle,the major organ responsible for glucose homeostasis,and activates 5'-AMP-activated protein kinase(AMPK),a signaling intermediary leading to metabolic enhancement of skeletal muscle.METHODS:Isolated rat epitrochlearis and soleus muscles were incubated in a buffer containing a CR water extract(CE),and activation of AMPK and related events were examined.RESULTS:In response to CE treat-ment,phosphorylation of Thr172 at the catalyticαsubunit of AMPK,an essential step for full kinase activation,increased in both mus-cles.Phosphorylation of Ser79 of acetyl CoA carboxylase(ACC),an endogenous substrate of AMPK,increased concomitantly.Analysis of isoform-specific AMPK activity revealed that CE activated both the α1 and α2 isoforms of the catalytic subunit.Importantly,the maximal effect of CE on AMPK phosphorylation was significantly greater than that of berberine(BBR),indicating that the action of CE is not totally ascribed to BBR.CONCLUSION:We propose that CE is an acute activator of AMPK in both fast-and slow-twitch skeletal muscles.

柚皮素对口腔鳞状细胞癌细胞的干预作用研究

目的:探究柚皮素(NRG)对口腔鳞状细胞癌(OSCC)细胞增殖、凋亡、迁移与侵袭的影响。方法:采用浓度(μmol/L)为0、5、10、15、20、25、30的NRG处理OSCC CAL-27细胞,CCK-8法检测细胞活力;将CAL-27细胞分为低、中、高剂量NRG组(NRG-L、NRG-M组、NRG-H组)、Compound C(AMPK抑制剂)组、NRG-H+Compound C组、对照组(NC组,正常培养),CCK-8与EdU染色、流式细胞术、划痕实验、Transwell分别检测细胞增殖、凋亡、迁移、侵袭;Western blot检测天冬氨酸特异性半胱氨酸蛋白酶-3(Caspase-3)、增殖细胞核抗原(PCNA)、基质金属蛋白酶(MMP)-2、MMP-9、磷酸化腺苷酸活化蛋白激酶(p-AMPK)、沉默信息调节蛋白1(SIRT1)、乙酰化核因子κB p65(Ac-NF-κB p65)蛋白表达。结果:选取5、10、20μmol/L NRG分别作为后续处理CAL-27细胞的低、中、高剂量;与NC组比较,NRG-L组、NRG-M组、NRG-H组EdU阳性率、划痕愈合率、A 450值、侵袭细胞数及MMP-2、PCNA、MMP-9、Ac-NF-κB p65蛋白下调,细胞凋亡率及p-AMPK、Caspase-3、SIRT1蛋白上调(P<0.05);与NC组相比,Compound C组EdU阳性率、划痕愈合率、A 450值、侵袭细胞数及MMP-2、PCNA、MMP-9、Ac-NF-κB p65蛋白升高,细胞凋亡率及p-AMPK、Caspase-3、SIRT1蛋白表达下调(P<0.05);Compound C逆转了高剂量NRG对CAL-27细胞增殖、迁移、凋亡及侵袭的影响。结论:NRG抑制CAL-27细胞增殖、迁移与侵袭,并诱导细胞凋亡,其机制可能与激活AMPK进而抑制NF-κB通路有关。

基于“肾脑相济”理论探讨艾灸对阿尔茨海默病大鼠海马AMPK/mTOR信号通路的影响

目的观察艾灸对阿尔茨海默病(Alzheimer’s disease,AD)大鼠腺苷酸活化蛋白激酶(adenosine 5-monophosphate activated protein kinase,AMPK)/雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号通路相关递质表达的影响,探讨艾灸治疗AD的作用机制。方法将SD大鼠按照随机数字表法分为正常组8只、模型组32只,采取侧脑室注射β淀粉样蛋白(amyloidβ-protein,Aβ)_(25-35)的方法建立大鼠AD模型。将模型复制成功的大鼠随机分为模型组、药物组、艾灸组,每组8只。艾灸组大鼠用艾条灸“百会”“肾俞”“三阴交”,每次15 min,同时按3 mg/kg灌胃蒸馏水;药物组大鼠按3 mg/kg灌胃盐酸多奈哌齐;对照组及模型组大鼠按3 mg/kg灌胃蒸馏水。采用Morris水迷宫法检测大鼠行为学表现,苏木精—伊红染色法观察大鼠海马病理组织改变,Western blot法检测大鼠海马磷酸化雷帕霉素靶蛋白(phosphorylated mammalian target of rapamycin,p-mTOR)、核糖体蛋白S6激酶(ribosomal protein S6 kinase p70,P70S6K)、自噬相关基因5(autophagy-related gene 5,ATG5)、磷酸化腺苷酸活化蛋白激酶(phosphorylated adenosine 5-monophosphate activated protein kinase,p-AMPK)、微管相关蛋白1轻链3B(microtubule associated protein light chain 3B,LC3B)-Ⅱ/LC3B-Ⅰ的表达水平。结果苏木精—伊红染色结果表明,模型组海马神经元萎缩明显,与模型组比较,药物组和艾灸组海马神经元形态及分化程度均有明显改善。与正常组比较,模型组大鼠的逃避潜伏期显著延长(P<0.05),p-mTOR及P70S6K表达水平均显著升高(P<0.05),ATG5、LC3B-Ⅱ/LC3B-Ⅰ、p-AMPK表达水平均显著降低(P<0.05)。与模型组比较,药物组和艾灸组大鼠的逃避潜伏期均显著缩短(P<0.05),p-mTOR及P70S6K表达水平均显著下降(P<0.05),ATG5、LC3B-Ⅱ/LC3B-Ⅰ、p-AMPK表达水平均显著上升(P<0.05)。与药物组比较,艾灸组大鼠逃避潜伏期显著缩短(P<0.05);p-mTOR及P70S6K表达水平显著降低(P<0.05),ATG5、LC3B-Ⅱ/LC3B-Ⅰ、p-AMPK表达水平均显著上升(P<0.05)。结论艾灸能够调控AMPK/mTOR信号通路,诱导细胞自噬,阻断脑内Aβ表达,从而改善认知功能。

金合欢素调节Sirt1/AMPK/Nrf2信号通路对糖尿病白内障大鼠氧化应激损伤的影响

目的探讨金合欢素对糖尿病白内障(DC)大鼠氧化应激损伤的影响及其对沉默调节蛋白1(Sirt1)/腺苷酸活化蛋白激酶(AMPK)/核因子E2相关因子2(Nrf2)信号通路的调控作用。方法60只SD大鼠随机分为对照组、模型组、金合欢素低剂量组、金合欢素高剂量组、金合欢素+Sirt1抑制剂(EX527)组,除对照组以外均构建DC大鼠模型,其中,金合欢素低剂量组、金合欢素高剂量组大鼠分别经颈部皮下注射10 mg·kg^(-1)、20 mg·kg^(-1)的金合欢素,金合欢素+EX527组大鼠经颈部皮下注射20 mg·kg^(-1)金合欢素,均为每天2次,同时金合欢素+EX527组大鼠经皮下埋入渗透微型泵每天泵入3.5 mg·kg^(-1)EX527,其余组别均泵入等量生理盐水,给药持续4周。给药结束后,测量血压和空腹血糖(FBG),裂隙灯照射法观察大鼠晶状体混浊状况,HE染色观察晶状体组织病理学变化,ELISA测定血清丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、白细胞介素(IL)-6、IL-1β的含量,Western blot检测Sirt1、p-AMPK、AMPK、Nrf2蛋白表达水平。结果与对照组相比,模型组大鼠晶状体上皮细胞呈片状、条索状,发生迁移性聚集,收缩压、FBG、晶状体混浊评分、MDA、IL-6、IL-1β水平均升高,SOD、GSH-Px含量及Sirt1、p-AMPK/AMPK、Nrf2蛋白表达水平均降低(均为P<0.05);与模型组比较,金合欢素低、高剂量组大鼠晶状体上皮细胞迁移性聚集现象改善,收缩压、FBG、晶状体混浊评分、MDA、IL-6、IL-1β水平均降低,SOD、GSH-Px含量及Sirt1、p-AMPK/AMPK、Nrf2蛋白表达水平均升高(均为P<0.05);与金合欢素高剂量组比较,金合欢素+EX527组晶状体上皮细胞形态改变和聚集现象加重,收缩压、FBG、晶状体混浊评分、MDA、IL-6、IL-1β水平均升高,SOD、GSH-Px含量及Sirt1、p-AMPK/AMPK、Nrf2蛋白表达水平均降低(均为P<0.05)。结论金合欢素可能通过激活Sirt1/AMPK/Nrf2通路保护DC大鼠免受氧化应激损伤。

Ginsenoside Rb1 Ameliorates Autophagy of Hypoxia Cardiomyocytes from Neonatal Rats via AMP-Activated Protein Kinase Pathway

Objective: To investigate whether ginsenoside-Rb1(Gs-Rb1) improves the CoCl2-induced autophagy of cardiomyocytes via upregulation of adenosine 5’-monophosphate-activated protein kinase(AMPK) pathway. Methods: Ventricles from 1-to 3-day-old Wistar rats were sequentially digested, separated and incubated in Dulbecco’s modified Eagle’s medium supplemented with 10% fetal bovine serum for 3 days followed by synchronization. Neonatal rat cardiomyocytes were randomly divided into 7 groups: control group(normal level oxygen), hypoxia group(500 μmol/L CoCl2), Gs-Rb1 group(200 μmol/L Gs-Rb1 + 500 μmol/L CoCl2), Ara A group(500 μmol/L Ara A + 500 μmol/L CoCl2), Ara A+ Gs-Rb1 group(500 μmol/L Ara A + 200 μmol/L Gs-Rb1 + 500 μmol/L CoCl2), AICAR group [1 mmol/L 5-aminoimidazole-4-carboxamide ribonucleotide(AICAR)+ 500 μmol/L CoCl2], and AICAR+Gs-Rb1 group(1 mmol/L AICAR + 200 μmol/L Gs-Rb1 + 500 μmol/L CoCl2). Cel s were treated for 12 h and cell viability was determined by methylthiazolyldiphenyl-tetrazolium bromide(MTT) assay and cardiac troponin I(cTnI) levels were detected by enzyme-linked immunosorbent assay(ELISA). AMPK activity was assessed by 2’,7’-dichlorofluorescein diacetate(DCFH-DA) ELISA assay. The protein expressions of Atg4 B, Atg5, Atg6, Atg7, microtubule-associated protein 1 A/1 B-light chain 3(LC3), P62, and active-cathepsin B were measured by Western blot. Results: Gs-Rb1 significantly improved the cell viability of hypoxia cardiomyocytes(P<0.01). However, the viability of hypoxia-treated cardiomyocytes was significantly inhibited by Ara A(P<0.01). Gs-Rb1 increased the AMPK activity of hypoxia-treated cardiomyocytes. The AMPK activity of hypoxia-treated cadiomyocytes was inhibited by Ara A(P<0.01) and was not affected by AICAR(P=0.983). Gs-Rb1 up-regulated Atg4B, Atg5, Beclin-1, Atg7, LC3B Ⅱ, the LC3BⅡ/Ⅰ ratio and cathepsin B activity of hypoxia cardiomyocytes(P<0.05), each of these protein levels was significantly enhanced by Ara A(all P<0.01), but was not affected by AICAR(all P>0.05). Gs-Rb1 significantly down-regulated P62 levels of hypoxic cardiomyocytes(P<0.05). The P62 levels of hypoxic cardiomyocytes were inhibited by Ara A(P<0.05) and were not affected by AICAR(P=0.871). Conclusion: Gs-Rb1 may improve the viability of hypoxia cardiomyocytes by ameliorating cell autophagy via the upregulation of AMPK pathway.

Mixture of five herbal extracts ameliorates pioglitazone-induced aggravation of hepatic steatosis via activating the adiponectin receptor 2/AMP-activated protein kinase signal pathway in diabetic KKAy mice

OBJECTIVE: To assess the effect of a mixture of five herbal extracts(FT-5) on insulin resistance, glucose/lipid metabolism, hepatic steatosis, and to investigate whether the combination of FT-5 and pioglitazone would provide a robust effect on diabetes treatment, while may minimize undesirable side-effects of pioglitazone in diabetic Ay gene(KKAy)mice.METHODS: Seven-week-old KKAy mice were randomly divided into five groups: control(CON)group, FT-5(2.0 g/kg) group, pioglitazone(20 mg/kg)(PIO) group, pioglitazone(20 mg/kg) + FT-5(2.0 g/kg)(P + F) group. Age-matched C57 BL/6 J micewere used as the control group. After seven weeks of continuous intragastric administration of medication, the glucose metabolism, insulin sensitivity and lipid metabolism of KKAy mice were evaluated by assessing the fasting blood glucose(FBG), oral glucose tolerance test(OGTT), fasting serum insulin(FINS), insulin tolerance test(ITT), homeostasis model of assessment-insulin resistance index(HOMA-IR), total cholesterol(TC), total triglycerides(TG), and free fatty acids(FFA) in plasma and liver.Plasma and hepatic adiponectin were measured via enzyme-linked immunosorbent assays. Genes related to adipogenesis and lipolysis in white adipose tissues(WAT) and liver were examined by real-time polymerase chain reaction. Lipid metabolism-related protein expression in the liver of KKAy mice were detected by Western blotting.RESULTS: PIO treatment remarkably improved insulin resistance. However, it also showed substantial side effects. FT-5 group exhibited no significant decrease in serum glucose. However, it reduced fasting plasma TG levels and improved hepatic steatosis of KKAy mice. P + F group showed improved insulin resistance and similar body weight gain, as compared with control group. The m RNA expression of genes related to fatty acid oxidation was markedly up-regulated in the liver of P + F group.Pioglitazone administration markedly decreased the phosphorylation levels of AMPK, as compared with all other groups. Besides, even though plasma adiponectin increased in PIO, FT-5, P + F group, adipo R2 gene expression significantly decreased in the liver of PIO group.CONCLUSION: FT-5 decreased plasma TG and alleviated aggravating hepatic steatosis induced by pioglitazone in KKAy mice. FT-5's mechanism might be associated with its ability to activate the Adipo R2/AMPK pathway.

基于AMPK/mTOR信号通路探讨人参-黄芪对人胃癌细胞自噬的影响

目的:探究益气扶正药人参-黄芪对人胃癌细胞自噬的影响,并探讨腺苷酸活化蛋白激酶(AMPK)/哺乳动物雷帕霉素靶蛋白(mTOR)信号通路在其中的作用机制。方法:将人胃癌细胞株(SGC-7901)随机分为对照组(人参-黄芪0 mg/ml)和人参-黄芪组(1、2、4、8、16、32、64 mg/ml),经药物处理后,CCK-8法观察人胃癌细胞增殖情况;筛选最佳浓度并将其作为后续实验中的实验组;MDC免疫荧光染色观察细胞自噬情况;Western blot法检测人胃癌细胞自噬相关蛋白(Beclin-1、LC3B)及AMPK/mTOR信号通路相关蛋白(AMPK、p-AMPK、mTOR及p-mTOR)的表达情况。结果:CCK-8法结果显示,人参-黄芪组人胃癌细胞增殖作用降低(P<0.01),且呈浓度依赖性;MDC染色荧光检测显示实验组的荧光强度显著增强(P<0.01),表明人参-黄芪可以诱导人胃癌细胞产生自噬;Western blot结果显示,实验组的Beclin-1、LC3B、p-AMPK/AMPK蛋白表达水平上升(P<0.01),p-mTOR/mTOR蛋白表达水平下降(P<0.01)。结论:人参-黄芪配伍能够抑制人胃癌细胞的增殖、促进人胃癌细胞自噬,其机制可能与激活AMPK/mTOR信号通路相关。

白藜芦醇通过AMPK-P53途径调节糖尿病心肌线粒体自噬的研究

目的观察白藜芦醇(RES)对糖尿病心肌线粒体自噬功能的影响并探讨其分子机制。方法 C57BL/6小鼠分为对照组、糖尿病组、RES组及RES+腺嘌呤核糖核苷酸依赖的蛋白激酶(AMPK)抑制剂组。小动物超声检测各组实验动物的左室收缩末内径、左室舒张末内径、左室收缩末期容积及左室舒张末期容积;计算左室射血分数及短轴缩短率。Western blotting检测各组实验动物Parkin、P62、P53及磷酸化的AMPK (pAMPK)的蛋白表达。结果与对照组相比,糖尿病小鼠心肌组织Parkin、p AMPK蛋白表达及左室射血分数、短轴缩短率显著降低,而P62、P53蛋白表达显著升高。给予RES处理后可以逆转上述改变,但RES的作用被AMPK抑制剂所阻断。结论 RES可能通过AMPK-P53途径增加糖尿病心肌线粒体自噬,改善心脏功能。